Diode checker

ABSTRACT

Embodiments of the invention are directed to using a DC multimeter configured for checking device amperage. A DC voltmeter is electrically-connected in series with the DC multimeter. A linear circuit is electrically connected in series between the DC multimeter and the DC voltmeter. A device under test is electrically-connected between positive and negative terminals of the DC voltmeter.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The invention described herein may be manufactured and used by or forthe government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

FIELD OF THE INVENTION

The invention generally relates to component testing devices and, moreparticularly, to diode testing devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary circuit diagram, according to some embodiments ofthe invention.

FIG. 2 is an exemplary circuit diagram, according to some embodiments ofthe invention.

FIG. 3 is an exemplary circuit diagram, according to some embodiments ofthe invention.

It is to be understood that the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not to be viewed as being restrictive of the invention, as claimed.Further advantages of this invention will be apparent after a review ofthe following detailed description of the disclosed embodiments, whichare illustrated schematically in the accompanying drawings and in theappended claims.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Embodiments of the invention may be understood more readily by referencein the following detailed description taking in connection with theaccompanying figures and examples. It is understood that embodiments ofthe invention are not limited to the specific devices, methods,conditions or parameters described and/or shown herein, and that theterminology used herein is for the purpose of describing particularembodiments by way of example only and is not intended to be limiting ofthe claimed embodiments. Also, as used in the specification and appendedclaims, the singular forms “a,” “an,” and “the” include the plural.

Embodiments relate to an apparatus and method for checking diodes,including radio frequency (RF) diodes. Embodiments of the invention maybe referred to as a diode checker, diode match maker, a low-currentdiode checker, a low-current diode match maker, a low current radiofrequency diode checker, a low current radio frequency diode matchmaker, and numerous other variations. Embodiments of the invention areparticularly useful in some testing environments, including on rangeswhere numerous types of tests are conducted, including various forms offlight testing.

In particular, it is beneficial to operate diodes within a range ofabout 40 to 90 microamps. In the past, specialized test equipment wasused to test diodes. Specialized equipment, of course, can be veryexpensive. Diodes can fail for a variety of reasons, including voltagespikes, current spikes, and general wear and tear.

In particular, diodes have failed in Superhetrodyne receivers whentrying to match current. For example, personnel must match a diode “B”to a diode “A,” which is supplied by a diode supplier. One solutionidentified by embodiments of the invention include using a commonmultimeter combined with a voltage divider with a current meter inline.In some embodiments, a diode with voltmeter is used to bias the diode,which is understood to mean running current through the diode. Someembodiments employ a voltage divider and a rotary switch. Thus, the goalis to match diodes, which one may consider as a technique of low currentmatch making. A person having ordinary skill in the art will recognizethat a “low current environment” in sometimes used synonymously with“low voltage environment.” Similarly, a person having ordinary skill inthe art will recognize that a low voltage environment is defined as lessthan or equal to 28 V. Conversely, a high voltage environment is definedas greater than 28 V.

Although embodiments of the invention are described in considerabledetail, including references to certain versions thereof, other versionsare possible. Examples of other versions include performing alternatecombinations and sequencing of the components to optimize performancebased on specific operating environments. Therefore, the spirit andscope of the appended claims should not be limited to the description ofversions included herein.

In the accompanying drawings, like reference numbers indicate likeelements. FIGS. 1 through 3 illustrate exemplary circuit diagrams,according to embodiments of the invention. Reference characters 10, 20,and 30 are directed to the embodiments shown in FIGS. 1, 2, and 3,respectively.

Apparatus Embodiments

Embodiments make use of standard electrical nomenclature, unless noted.For instance, direct current is abbreviated as DC. Voltage isabbreviated as V. Current is abbreviated as A for amps. Resistance,measured in ohms is sometimes abbreviated as Ω. An embodiment shown inFIG. 1 depicts a device checker (reference character 10). The devicechecker 10 includes a first DC multimeter 14. The first DC multimeter 14provides source voltage. The first DC multimeter 14 has a positiveterminal 14 a which may be considered the source. The first DCmultimeter 14 has a negative terminal 14 b.

A second DC multimeter 18 is electrically-connected in series with thefirst DC multimeter 14. The second DC multimeter 18 has a positiveterminal 18 a and a negative terminal 18 b. Both the first and second DCmultimeters 14 & 18 are configured for checking device amperage.

A linear circuit 19 is electrically-connected in series between thenegative terminal 14 b of the first DC multimeter 14 and the positiveterminal 18 a of the second multimeter 18. A device under test (DUT) 12is electrically-connected between the positive 18 a and negative 18 bterminals of the second DC multimeter 18. The DUT 12 is a diode. In someembodiments, the DUT 12 is a radio frequency diode. The linear circuit19 is a voltage divider.

As shown in FIG. 1, the linear circuit 19 has a first resistor, R1,electrically connected in series to a third DC multimeter 16. The thirdDC multimeter has a positive and a negative terminal 16 a & 16 b. Thefirst resistor, R1, is electrically connected in series between thenegative terminal 14 b of the first DC multimeter 14 and the positiveterminal 16 a of the third DC multimeter 16. A second resistor, R2, iselectrically-connected in series between the negative terminal 16 b ofthe third DC multimeter 16 and the positive terminal 18 a of the secondDC multimeter 18.

As shown in FIG. 1, the first resistor, R1, is a 7.3 kiliohm resistor.The second resistor, R2, is a variable resistance 200 kiliohm resistor.Based on this, one having ordinary skill in the art will recognize thatthe DUT 12 can be matched to a particular amperage for diodes that turnon from 0 to 100 microamps, commonly abbreviated as 0 to 100 μA. Amicroamp is understood in the art to be 1×10⁻⁶ A.

In another embodiment shown in FIG. 2, a circuit diagram of a devicechecker 20 is depicted. The device checker 20 includes a DC multimeter24 configured to check device amperage. The DC multimeter 24 has apositive terminal 24 a and a negative terminal 24 b. The DC multimeter24 provides source voltage and, thus, its positive terminal 24 a isconsidered the source. A DC voltmeter 26 is electrically-connected inseries with the DC multimeter 24. The DC voltmeter 26 has a positiveterminal 26 a and a negative terminal 26 b. The DC voltmeter's (26)negative terminal 26 b is considered common. The DC voltmeter 26 has arange of about 0 to 2 V_(DC).

A linear circuit 22 is electrically-connected in series between thepositive terminal 24 a of the DC multimeter 24 and the positive terminal26 a of the DC voltmeter 26. A device under test (DUT) 12electrically-connected between the positive 26 a and negative terminals26 b of the DC voltmeter 26. The DUT 12 is a diode. In some embodiments,the DUT 12 is a radio frequency diode. The linear circuit 22 is avoltage divider.

As shown in FIG. 2, the linear circuit 22 has a first resistor, R1,electrically connected in series to a DC ammeter 28. A rotary switch 23is electrically-connected in parallel with the DC ammeter 28. As shownin FIG. 2, the rotary switch has two poles (shown as referencecharacters 25A & 25B), which may be referred to as a first pole and asecond pole or as a first switch and a second switch. If preferred, thefirst and second switches 25A & 25B may, instead, be referred to assub-switches for nomenclature variance. Reference characters 27 and 29are junction points that connect the rotary switch 23 in parallel withthe DC Ammeter 28. As illustrated, the junction points 27 & 29 areelectrically connected to the two poles/sub-switches 25A & 25B.

The rotary switch 23 is a single dial that is turned by a user to adjustresistances. The dial is not shown in FIG. 2 for ease of viewing. A pairof levers may, instead, be employed in place of a dial. The rotaryswitch 23 has, via sub-switches 25A & 25B, four contacts (25A1 through25A4 & 25B1 through 25B4) on each sub-switch, corresponding to fourpositions on each sub-switch. As shown on FIG. 2, the rotary switch 23has a first position (reference character 25A1 & 25B1), a secondposition (25A2 & 25B2), a third position (25A3 & 25B3), and a fourthposition (25A4 & 25B4).

FIG. 2 depicts the rotary switch in its first position because the firstand second sub-switches 25A & 25B are each directed to its respectivefirst contact 25A1 & 25B1. The rotary switch in its first positiondirects current through a second resistor, R2. Similarly, when therotary switch closes contact with the second contact 25A2 & 25B2, therotary switch is in its second position and directs current through afourth resistor, R4. Likewise, when the rotary switch closes contactwith the third contact 25A3 & 25B3, the rotary switch is in its thirdposition and directs current through a third resistor, R3.

As shown in FIG. 2, a fourth position corresponds to the rotary switchbeing in its fourth position, which corresponds to no resistance. Afifth resistor, R5, is electrically connected in series between thejunction point 29 and the positive terminal 26 a of the DC voltmeter 26.

In the embodiment depicted in FIG. 2, the first resistor, R1, is a 5.5kiliohm resistor. The second resistor, R2, is a 200 ohm resistor at a 1milliamp scale. The third resistor, R3, is a 1200 ohm resistor at a 250microamp scale. The fourth resistor, R4, is a 450 ohm resistor at a 500microamp scale. The fifth resistor, R5, is a variable resistance 200kiliohm resistor. Based on this, one having ordinary skill in the artwill recognize that the DUT 12 can be matched to a particular amperageby switching the rotary switch 23, thereby varying the resistance.

The embodiment shown in FIG. 3, depicted with reference character 30, isdirected to a prototype model constructed for field use and based onwhat was available. The concepts employed in the FIG. 3 embodiment issimilar to FIG. 2, however the FIG. 3 embodiment offers the potentialfor expansion, which would be use in instances where higher currentswould be experienced—such as in a high voltage scenario.

FIG. 3 illustrates a circuit diagram of the device checker 30. Thedevice checker 30 includes a DC multimeter 34 configured to check deviceamperage. The DC multimeter 34 has a positive terminal 34 a and anegative terminal 34 b. The DC multimeter 34 provides source voltageand, thus, its positive terminal 34 a is considered the source. A DCvoltmeter 36 is electrically-connected in series with the DC multimeter34. The DC voltmeter 36 has a positive terminal 36 a and a negativeterminal 36 b. The DC voltmeter's (36) negative terminal 36 b isconsidered common. The DC voltmeter 36 has a range of about 0 to 2V_(DC).

A linear circuit 32 is electrically-connected in series between thepositive terminal 34 a of the DC multimeter 34 and the positive terminal36 a of the DC voltmeter 36. A device under test (DUT) 12electrically-connected between the positive 36 a and negative terminals36 b of the DC voltmeter 36. The DUT 12 is a diode. In some embodiments,the DUT 12 is a radio frequency diode. The linear circuit 32 is avoltage divider.

As shown in FIG. 3, the linear circuit 32 has a first resistor, R1,electrically connected in series to a DC ammeter 38. A rotary switch 33is electrically-connected in parallel with the DC ammeter 38. As shownin FIG. 3, the rotary switch has two active poles (shown as referencecharacters 35A & 35B), which may be referred to as a first pole and asecond pole or as a first switch and a second switch. If preferred, thefirst and second switches 35A & 35B may, instead, be referred to assub-switches for nomenclature variance. Reference characters 37 and 39are junction points that connect the rotary switch 33 in parallel withthe DC Ammeter 38. As illustrated, the junction points 37 & 39 areelectrically connected to the two poles/sub-switches 35A & 35B.

The rotary switch 33 is a single dial that is turned by a user to adjustresistances. The dial is not shown in FIG. 3 for ease of viewing. Leversmay, instead, be employed in place of a dial. The rotary switch 33 has,via sub-switches 35A & 35B, four contacts (35A1 through 35A4 & 35B1through 35B4) on each sub-switch, corresponding to four positions oneach sub-switch. As shown on FIG. 3, the rotary switch 33 has a firstposition (reference character 35A1 & 35B1), a second position (35A2 &35B2), a third position (35A3 & 35B3), and a fourth position (35A4 &35B4).

FIG. 3 depicts the rotary switch in its first position because the firstand second sub-switches 35A & 35B are each directed to its respectivefirst contact 35A1 & 35B1. The rotary switch in its first positiondirects current through a second resistor, R2. Similarly, when therotary switch closes contact with the second contact 35A2 & 35B2, therotary switch is in its second position and directs current through afourth resistor, R4. Likewise, when the rotary switch closes contactwith the third contact 35A3 & 35B3, the rotary switch is in its thirdposition and directs current through a third resistor, R3.

As shown in FIG. 3, a fourth position corresponds to the rotary switchbeing in its fourth position, which corresponds to no resistance. Afifth resistor, R5, is electrically connected in series between thejunction point 39 and the positive terminal 36 a of the DC voltmeter 36.

In the embodiment depicted in FIG. 3, the first resistor, R1, is a 5.5kiliohm resistor. The second resistor, R2, is a 200 ohm resistor at a 1milliamp scale. The third resistor, R3, is a 1200 ohm resistor at a 250microamp scale. The fourth resistor, R4, is a 450 ohm resistor at a 500microamp scale. The fifth resistor, R5, is a variable resistance 200kiliohm resistor. Based on this, one having ordinary skill in the artwill recognize that the DUT 12 can be matched to a particular amperageby switching the rotary switch 33, thereby varying the resistance.

It is apparent to a person having ordinary skill in the art that theembodiment shown in FIG. 3 offers the opportunity for expansion, ifneeded. Additional poles/switches are depicted using referencecharacters 35C, 35D, 35E, and 35F along with the respectivecorresponding contacts depicted with reference characters 35C1 through35F4. A person having ordinary skill in the art will recognize that therotary switch 33 in FIG. 3 is a two-deck, triple pole rotary switch,which provides more physical space for switching (if needed).

Using Embodiments of the Invention

In embodiments, the DC multimeters (14, 24, & 34) are configured indiode testing mode. The DUT 12 has an amperage range of about 40microamps to about 90 microamps. Stated another way, a user ofembodiments of the invention has a goal of matching a diode to anamperage range of about 40 microamps to about 90 microamps.

Upon connecting the components using standard patch cords, and poweringup the source the source (the DC multimeters depicted with referencecharacters 14, 24, and 34), the user adjusts the multimeters to operatein diode mode (diode checking mode). The user then adjusts current usingthe rotary switch. User selection of the rotary switch (23 & 33) allowsthe user to match diodes. Additionally, the second, third, and fourthresistors (R2, R3, & R4) are scalars configured to protect the DCAmmeter. The variable resistance resistor (R5) is configured to adjustthe current level within the scale of the readable range of the DCAmmeter 28 & 38. This assures that the DC Ammeter 28 & 38 is readingproperly. Upon diode matching, a pair of matching diodes is used in thereceiver systems.

In all embodiments, a project box may be implemented to house thecircuitry and protect it from damage caused by weather and beingdropped. A person having ordinary skill in the art will recognize thatembodiments of the invention, when used with a project box, can beconsidered a kit. In particular, the embodiment shown in FIG. 3 wasincorporated into a box having dimensions of about 5 inches×7 inches×4inches.

In the embodiments depicted in FIGS. 2 & 3, the second, third, andfourth resistors (R2, R3, & R4) each have a respective scale. Asdiscussed above, the second resistor, R2, has a resistance of about 200ohms at a 1 mA (1 milliamp) scale. Thus, when the rotary switch 23 & 33is in the first position (reference character 25A1/25B1 & 35A1/35B1),the current going to the DC Ammeter 28 & 38 changes from 0 to 1 mA.Similarly, the third resistor, R3, has a resistance of about 1200 ohmsat a 250 μA scale. Therefore, when the rotary switch 23 & 33 is in thethird position (reference character 25A3/25B3 & 35A3/35B3), the currentgoing to the DC Ammeter 28 & 38 changes from 0 to 250 μA. The fourthresistor, R4, has a resistance of about 450 ohms at a 500 μA scale.Therefore, when the rotary switch 23 & 33 is in the second position(reference character 25A2/25B2 & 35A2/35B2), the current going to the DCAmmeter 28 & 38 changes from 0 to 500 μA. Finally, when the rotaryswitch 23 & 33 is in the fourth position (reference character 25A4/25B4& 35A4/35B4), the current going to the DC Ammeter 28 & 38 changes from 0to 100 μA, because the DC Ammeter is a 0 to 100 μA rated ammeter.

While the invention has been described, disclosed, illustrated and shownin various terms of certain embodiments or modifications which it haspresumed in practice, the scope of the invention is not intended to be,nor should it be deemed to be, limited thereby and such othermodifications or embodiments as may be suggested by the teachings hereinare particularly reserved especially as they fall within the breadth andscope of the claims here appended.

What is claimed is:
 1. A device checker, comprising: a DC multimeterconfigured for checking device amperage, said DC multimeter having apositive terminal and a negative terminal; a DC voltmeterelectrically-connected in series with said DC multimeter, said DCvoltmeter having a positive terminal and a negative terminal; a linearcircuit electrically-connected in series between said positive terminalof said DC multimeter and said positive terminal of said DC voltmeter;and a device under test (DUT) electrically-connected between saidpositive and negative terminals of said DC voltmeter; wherein saidlinear circuit is a voltage divider, comprising: a first resistor, R1; aDC ammeter electrically-connected in series with said first resistor,R1; a rotary switch electrically-connected in parallel with said DCammeter, said rotary switch having a first position, a second position,a third position, and a fourth position; said first positioncorresponding to a second resistor, R2, said second positioncorresponding to a fourth resistor, R4, said third positioncorresponding to a third resistor, R3, and said fourth positioncorresponding to no resistance; and a fifth resistor, R5,electrically-connected in series with said DC ammeter.
 2. The devicechecker according to claim 1, wherein said first resistor, R1, has aresistance of about 5.5 kiliohms.
 3. The device checker according toclaim 1, wherein said second resistor, R2, has a resistance of about 200ohms at about a 1 milliamp scale.
 4. The device checker according toclaim 1, wherein said third resistor, R3, has a resistance of about 1200ohms at about a 250 microamp scale.
 5. The device checker according toclaim 1, wherein said fourth resistor, R4, has a resistance of about 450ohms at about a 500 microamp scale.
 6. The device checker according toclaim 1, wherein said fifth resistor, R5, has a variable resistance ofabout 200 kiliohms.
 7. The device checker according to claim 1, whereinsaid DUT is a radio frequency diode.